Bathroom soils can be especially tenacious and difficult to remove. In particular, soils found on tub and shower surfaces are typically comprised in large part of insoluble calcium and magnesium salts of fatty acids (i.e., the products from reaction of the calcium and magnesium ions found in hard water with the various soaps used for bathing), together with smaller amounts of mineral deposits, dirt, oil, grease, fatty substances from the body (e.g., sebum), and chemical residues from hair grooming products and the like. This "soap scum" is quite unsightly and can be unhealthy as well, affording a breeding ground for mold, mildew, fungus, and bacteria.
A number of hard surface cleaners have been specially formulated to target bathroom soils. These cleaners may include such constituents as surfactants, chelants or sequestrants for assisting with the removal of soaps and mineral deposits, buffers, agents for combating mildew and fungus (e.g., liquid sodium hypochlorite), bacteriostats, dyes, fragrances, and the like in order to provide performance and/or aesthetic enhancements. In general, hard surface cleaners are applied by pouring, by application with a cloth or sponge, or by spraying in either an aerosol or non-aerosol fashion.
After application to tub and shower surfaces, most conventional cleaners require that the user expend a great deal of energy in removing the bathroom soil by scrubbing and wiping with the aid of a sponge or brush. The composition of these cleaners may be harsh to human skin, or at least somewhat irritating to sensitive skin, thereby additionally presenting the inconvenience that protective gloves be donned for the scrubbing and wiping.
Recently a new type of cleaner for tub and shower surfaces has become available to the consumer, the use of which requires neither scrubbing nor wiping. Rather, the cleaning composition is applied to those surfaces by spraying or rinsing after (preferably) each showering in what might be considered to be a "preventive maintenance" mode of operation. The dissolution and freeing of any formed soil is caused to occur in an efficient manner such that with each subsequent showering, the freed soil may be washed down the drain without the need for scrubbing or wiping or the like. The shower is kept in a continuously clean state. This new type of cleaner may be denoted a "shower rinsing" composition or cleaner.
It will be apparent that, upon application of such a shower rinsing composition, ideally there would be no apparent streaking, filming or residue to spoil the surface appearance. If such were otherwise, some wiping might be necessary to restore the appearance of a clean surface, and this would defeat, at least in some measure, a primary purpose of the product. It is highly desirable, then, that a shower rinsing cleaner yield an exceptionally clean-looking surface merely by spraying.
Disclosed in U.S. Pat. No. 5,536,452, issued to Black, is a method for using a shower rinsing composition. The composition comprises a nonionic surfactant variously described as having an hydrophilic-lipophilic balance ("HLB") value of either "13 or less" or "13.0 or less," an alcohol, and a chelating agent. The composition has a pH of 4-8. The preferred nonionic surfactant is stated to be ANTAROX BL-225, a linear mixed ethylene glycol ether, which has an HLB of 12. Other nonionic surfactants which are specifically called-out in the patent include alkylphenol glycol ethers, sorbitan oleic ester, and silicone polyalkoxylate block copolymers. (U.S. Pat. No. 5,536,452, also issued to Black, is essentially a more narrowly claimed version of the preceding Black method patent.)
Black explicitly teaches that nonionic surfactants having an HLB of greater than 13 are unsatisfactory in the compositions of his patents (e.g., in the exemplary formulations of Table I of each of the patents, a nonionic surfactant having an HLB of 13 is described as only "marginally satisfactory," while other nonionic surfactants having an HLB of 14 and higher are graded as "unsatisfactory"). Black fails to teach, disclose or suggest that a shower rinsing composition might utilize a glycoside as the nonionic surfactant. Indeed, Black teaches entirely away from this class of surfactant, as will be discussed below.
The compositions of the two Black patents are disadvantageous in at least two respects. For one, use of the suggested nonionic surfactants results in compositions that are cloudy at only slightly above room temperature. They therefore yield a product that is really only aesthetically presentable to the consumer when contained in an opaque bottle, whereas, modernly, it is desirable to be able to display a liquid cleaner in a clear container. For another, the streaking and filming characteristics afforded when using the surfactants of Black have been found to be not nearly so good as what is indicated in those patents--at least not relative to what quality of surface appearance has now been found might actually be obtained by use of the invention to be disclosed herein.
Disclosed in PCT International App. No. WO 98/02511 (published Jan. 22, 1998), also to Black, is essentially a further embodiment of the invention of U.S. Pat. Nos. 5,536,452 and 5,536,452. Here it is revealed that an anionic surfactant such as N-acyl-N,N'-ethylenediaminetriacetic acid may function as both the surfactant and the chelating agent for an acidic formula shower rinsing composition. Additionally, in the case where a separate surfactant and chelating agent are employed, the classes of suitable surfactants have been expanded. Now called out for the surfactant component are amine oxides, imidazoline derivatives, betaines, quaternary ammonium compounds, amphoteric surfactants, sulfonates and alkyl sulfates, ether carboxylates, sarcosines, iesethionates, phosphoterics and phosphate esters. The compositions of this application are preferably at a pH of 4-6.
Notably, the Black PCT application indicates that small quantities of "super wetting surfactants," such as a silicone glycol copolymer or pyrilidone, may also be added to prevent streaking on shower surfaces, which would suggest that the disclosed compositions are not entirely free from exhibiting undesired streaking.
Disclosed in Japanese Kokai Pat. App. No. Hei 10[1998]-08,090 (published Jan. 13, 1998) is a detergent composition for hard surfaces, in particular for the bathroom, containing a glycoside having the structure: EQU R.sup.1 O--(Z).sub.n
where R.sup.1 represents a hydrocarbon group with an average number of carbon atoms of 8.0-9.5, Z represents a residue derived from a reducing sugar, and n is a number in the range of 1-2 and represents the average degree of polymerization of the residual group Z. Use of glycosides having these parameters are reported to give the best combination of detergency, foaming power and rinsing characteristics for the cleaner. It is preferred that the formula also contain a polyether sulfuric acid ester salt where additional detergency is required. Also preferred is the inclusion of a glycol ether and a chelant, such as the disodium salt of ethylenediaminetetraacetic acid (EDTA). The preferred pH for the composition is stated to be 6.0-8.0. There is no suggestion that the compositions might be formulated as a shower rinsing composition or that they might be used in that manner.
None of the prior art teaches, discloses or suggests the use of a glycoside as the surfactant portion in a shower rinsing composition with the surprising advantage of greatly improved streaking and filming performance as compared to other nonionic surfactants and wherein the best performing glycosides, surprisingly, exhibit an HLB value of greater than 13, and further wherein even alkaline shower rinsing compositions which contain a glycoside as surfactant are found to perform significantly better than acidic formulations containing other nonionic surfactants.